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1392 Chapter 16: Material Editor, Materials, and Maps
Index Of Refraction (out)—
Sets the IOR on the other
sideofasurface.Whensettothedefaultofzero,
this control has no effect. See the sect ion “Adjacent
Refractive Materials,” above. Default=0.0.
Persistence Distance—In conjunction with the
Light Persistence color, controls the percentage of
lightthatthevolumetransmits.Itisthedistance
at w hich light t ransmission is reduced to the
percentage specified by the Light Persistence RGB
values. Default=1.0.
If you specify an Outside Light Persistence color,
that setting also uses the Persistence Distance.
Ignore Normals—When on, the renderer do es
not use normals to decide whether a light ray
is entering or leaving the object. Normally, the
material uses norma ls to decide whether a ray is
entering or leaving an object. (It is entering if the
normal points toward the ray, leavi ng if the nor mal
points away from the ray .) This can present a
problem for rendering objects whose normals are
not unified. hen Ignore Normals is on, the material
decides whether a ray is entering or leaving t he
object by counting the number of times the ray has
intersected the object. Default=off.
Opaque Alpha—When on, refracted rays that touch
the environment don’t generate a transparent
alpha value. (This is how 3ds Max usually treats
the environment.) When off, refracted rays that
touch the environment render a transparent
alpha value, which can help if you plan to use the
rendering as part of a composite. Default=off.
Phong Coefficient—When greater than zero,
generates Phong highlights on the material. The
high lights appear in the sample slot. In general
thisvaluemustbegreaterthan10forhighlightsto
be apparent. Default=0.0.
Subsur face Scattering (SSS)
Mater ials
Material Ed itor > Type button > Material/Ma p Browser
> Choose SSS Fast Material (mi), SSS Fast Skin Material
(mi), SSS Fast Skin Mater ial+Displace (mi), or SSS Physical
Material (mi), and then click OK.
Note: The SSS materials do no t a ppear in the Browser
unless you have enabled the mental ray extensions by
using the mental ray Preferences panel. In addition, you
can’tassignshaderstotheoptionsinthisrolloutunless
the mental ray renderer is the currently active renderer.
The subsurface scattering (SSS) materials are
provided especial ly to model skin and other
organic materials whose appeara nce depends on
more than one layer of light scattering. 3ds Max
provides four of these materials. Each material is a
top-level wrapper (a “phenomenon”) for shaders
whose controls are documented in the
Standard
mental ray Shader Librar ies
document. Click a
link to see the mental images documentation for
the shader.
Tip: When you follow a link to the documentation
for mental images library shaders, scroll up a bit in
your browser. The links tend to go past the title
of the section, and there might be introductory
content above the link lo cation. If the link goes to
the b eginning of a section, scroll down instead.
Mater ial Name mi Library Shader Name
SSS Fast Material (mi) misss_f ast_simple_phe n
SSS Fast Skin Material (mi) misss_ fast_skin_phen
SSS Fast Skin
Material+Displace (mi)
misss_ fast_skin_phen_d
SSSPhysicalMaterial(mi) misss_physical
Also see Subsurface Scattering Shaders and t he
topics that follow it for more general information.
See P
hysical ly Correct Subsurface Scattering
for background information and tips about the
Physical material.